1. Field of the Invention
This invention pertains generally to methods and apparatus for the forming of pattern-creped fibrous products, and to the resulting creped fibrous products.
2. Description of the Prior Art
One method that has commonly been employed to break up the inter-fiber bonds in a formed web is by creping the web, usually as it comes off a drying drum which may be a Yankee dryer. In the typical creping operation, the web is pressed with a smooth roller onto a heated polishd metal drum, such as the Yankee dryer, while it is partially wet and before final drying. The heat of the dryer cylinder and the pressing with the roller causes the web to adhere to the surface of the cylinder as the moisture in the web is evaporated, with the dried web creped off the cylinder by a doctor blade.
The conventional creping process prepares the web for creping by pressing the web onto the dryer cylinder with a smooth roller. In addition, the prior art has recognized to some extent that variations in the creped paper product can be achieved by operations on the web while adhering the web to the cylinder, or by operations on the web while on the cylinder. As illustrated by the Tompkins et al. patent, U.S. Pat. No. 1,196,181, the prior art has recognized that a paper web can be water-marked by pressing the web with a watermark pattern while on a drying cylinder. Another Tompkins et al. patent, U.S. Pat. No. 1,143,333, taught that pressing the web while on the cylinder with a pressure roll having annular projections results in the pressed portions of the web having greater strength than the unpressed portions.
In the Sanford patent, U.S. Pat. No. 3,301,746, the web is pressed onto the drying cylinder with a knuckled fabric to achieve increased adhesion in the spot pattern of the knuckles. A similar knuckled fabric is pressed into a paper web after the web has been adhered to the drying cylinder in the Justus patent, U.S. Pat. No. 3,537,954. The prior art has also recognized that the creping can be affected through the patterned application of a bonding and adhering agent, in British patent specification No. 1,294,794, issued to the Scott Paper Company.